Our objective is to establish a colony of highly asthmatic dogs to act as exprimental models to study the pathophysiology of allergic reactions, and to develop new therapeutic methods. Our previous screening of dogs revealed that about 5% were allergic to grass pollens. We plan to screen by allergy skin tests and symptoms to locate allergic animals; these will be bred. Dogs reacting positively to pollen extracts will be exposed to inhalatic of nebulized pollen to ascertain if they are asthmatic. Pairs of dogs with positive reaction to inhaled pollens will be bred. The pups will be regularly exposed in chambers to nebulized pollens. Periodic serial bleedings will be made to immunologically test for pollen sensitivity. RAST, leukocyte histamine release, and lymphocyte transformation will be assayed. Pups will be concomitantly exposed to live virus infections (attenuated distemper or canine parainfluenza). If virus infections are found to initiate atopic sensitization and asthma in the pups, the mechanism of virus action will be explored. The effects of the virus will be counteracted, if possible by cyclic nucleotide-acting drugs and immunizations. In preliminary selection and breeding of IgE-skin reactive dogs, we have already 5 litters of pups. These have been immunized with pollen extracts 3 days after distemper immunization; 20/33 of these pups have developed IgE antibodies to the pollens. A canine model of asthma will have important application to the study of asthma in man because events leading to allergy can be simulated in the laboratory. Such events may be prevented by drugs or immunizations. Furthermore, such a model will be useful in testing new drugs and immunotherapeutic methods for treating asthma.